Best I have found is continued practice of overhand grip heavy deadlifts. The thicker the bar the better. Also, make it a habit to use the thicker bars if your

Best I have found is continued practice of overhand grip heavy deadlifts. The thicker the bar the better. Also, make it a habit to use the thicker bars if your gym has an option. I've also heard a towel and pullup bar is another option. Wrap the towel around the pullup bar and hang on it as long as possible. I've never done this method.